Adjustable arrangement for bending of bars of reinforcing steel mats

ABSTRACT

An arrangement for bending of reinforcing steel mats with a fixed support beam having a bearing surface for receiving and supporting a reinforcing steel mat. An exchangeable bending mandrel is adapted to be mounted on said bearing surface. A pivoting bar engaging beam, having a pivot axis disposed parallel to the bearing surface, is provided with a bending bar. A plurality of spaced hooklike holding mandrels are coaxially operatively mounted over the bearing surface. The bending bar is adapted to coact with the holding mandrels which hold down a steel mat to bend the bars of the steel mat around the bending mandrel. Hydraulic adjusting means are operatively connected, on the one hand, to the bar engaging beam and, on the other hand, to the fixed support beam and are adapted to adjust the arcuate path of the bending bar. The hydraulic adjusting means comprises a cylinder and double acting piston reciprocally mounted therein and dividing the cylinder into two chambers. Closeable valve means connect by conduit means both chambers to each other.

United States Patent 1 91 Bock [451 Feb. 25, 1975 1 ADJUSTABLE ARRANGEMENT FOR BENDING OF BARS OF REINFORCING STEEL MATS [76] Inventor: Rudolf Bock, Palmeistr. 9, 7031 Holzgerlingen, Germany [22] Filed: July 25, 1973 [21] Appl. No.: 382,583

[30] Foreign Application Priority Data Aug. 2, 1972 Germany 2237895 [52] US. Cl 72/321, 72/388, 140/107 [51] Int. Cl B2ld 11/12 [58] Field of Search 72/35, 219, 319, 320, 321, 72/388; 140/107 [56] References Cited UNITED STATES PATENTS 3,120,257 2/1964 Webers et a1. 72/321 3,273,371 9/1966 Peterson 72/319 FOREIGN PATENTS OR APPLICATIONS 1,283,790 11/1968 Germany 72/388 Primary ExaminerLowell A. Larson 57 ABSTRACT An arrangement for bending of reinforcing steel mats with a fixed support beam having a bearing surface for receiving and supporting a reinforcing steel mat. An exchangeable bending mandrel is adapted to be mounted on said bearing surface. A pivoting bar engaging beam, having a pivot axis disposed parallel to the bearing surface, is provided with a bending bar. A plurality of spaced hooklike holding mandrels are coaxially operatively mounted over the bearing surface. The bending bar is adapted to coact with the holding mandrels which hold down a steel mat to bend the bars of the steel mat around the bending mandrel. Hydraulic adjusting means are operatively connected, on the one hand, to the bar engaging beam and, on the other hand, to the fixed support beam and are adapted to adjust the arcuate path of the bending bar. The hydraulic adjusting means comprises a cylinder and double acting piston reciprocally mounted therein and dividing the cylinder into two chambers. Closeable valve means connect by conduit means both chambers to each other.

6 Claims, 5 Drawing Figures ADJUSTABLE ARRANGEMENT FOR BENDING OF BARS OF REINFORCING STEEL MATS This invention relates to an arrangement for bending of reinforced steel mats, wherein a plurality of bending mandrels are disposed on a supporting surface in spaced relationship to each other and coact with a bending bar of a bar engaging beam for bending the individual rods of the reinforcing steel mat. The bending mandrels are exchangeably mounted on the supporting surface. The arcuate path of the bending bar can be adjusted by means of special hydraulic means.

BACKGROUND OF THE INVENTION Installation of the aforedescribed type are already known in the art and are for example disclosed in my copending application Ser. No. 288,152, filed Sept. II, 1972 now U.S. Pat. No. 3,774,434.

SUMMARY OF THE INVENTION It is accordingly a primary object of the present invention to provide an installation for bending reinforced steel mats, wherein the adjustability of the path of the bending bar is improved so that the bending bar may be adjusted in a step-less manner while the hydraulic means effecting the adjusting of the bending bar also prevent an overloading of the bending mechanism.

The object of the invention is obtained in that between the bending bar and the supporting surface there is arranged a connecting mechanism including hydraulic means. The hydraulic means include a cylinder in a double acting piston disposed within the cylinder and dividing the cylinder into two chambers. These chambers are in communication with each other by means of conduits in which at least one closeable valve means is disposed. The afore-recited connecting mechanism comprises all types of supporting, connecting, and the driving members of the machine, which are mounted between the bending bar and the supporting surface and thus form jointly the bending mechanism for the machine.

The adjusting means form a closed hydraulic system which include a connecting channel for adjusting the piston relative to the cylinder, said connecting channel can be opened but is normally closed. The two chambers within the cylinder are advantageously connected by means of an excess pressure valve which opens when a predetermined limit pressure is exceeded and thus introduces an adjusting movement of the bending bar. The adjusting arrangement can, however, also include an hydraulic system wherein the piston is adjusted in dependency with the swinging movement of the bar engaging beam during the pivoting of the bar engaging beam. This type of an arrangement can also be controlled by means of the counter-pressure that builds up in the hydraulic system. The cylinder can be mounted at the supporting surface so that it pivots about the swing axis of the bar engaging beam or pivots about an axis which is parallel to said pivoting axis.

Thus the present invention constitutes an improvement over the installation which is disclosed and claimed in my co-pending application Ser. No. 288,152, filed Sept. 11, 1972 now U.S. Pat. No. 3,774,434. In the installation of my co-pending application the bar engaging beam is mounted on two concentrically arranged types which are rotatable relative to each other. One of these pipes is connected to the bar engaging beam and the other of these pipes is connected via supporting arms on the fixed support beam. The hydraulic adjusting means are constructed and arranged in the connecting mechanism so that the pipe which supports the bending arm is connected with a lever arm to the piston rod of the hydraulic means while the cylinder is pivotally connected to the fixed support beam. The hydraulic adjusting means can, in this form of the invention, be also mounted between the bending bar and the bar engaging beam, whereby the piston rod of the hydraulic adjusting means is connected with one of the concentric coaxially arranged pipes and the cylinder of the hydraulic adjusting means is connected with the other of the coaxial pipes, said two coaxial pipes forming the bar engaging beam.

DESCRIPTION OF DRAWINGS The invention is illustrated by way of example in the accompanying drawing which forms part of this application and in which:

FIG. 1 is a schematic elevational view of the entire installation for bending reinforcing steel mats in accordance with a first embodiment of the invention;

FIG. 2 is a partial side elevational view of the bending machine, wherein the bending mechanism and the hydraulic adjusting means are illustrated;

FIG. 3 is a partial side-elevational view similar to FIG. 2 except that the bending mandrel has been omitted;

FIG. 4 is a partial side-elevational view of a modified hydraulic adjusting means forming a second embodiment of the invention; and

FIG. 5 is a view of the modified hydraulic adjusting means of FIG. 4, wherein the bending machine has been rotated by DESCRIPTION OF PREFERRED EMBODIMENTS Referring now to FIG. 1 there is schematically illustrated the entire installation for bending reinforcing steel mats, hereinafter referred to as the bending machine. This machine comprises a fixed supporting beam 11 mounted on a pair of support columns 10. A plurality of hook-like bending mandrels 12 are mounted in a row on the supporting beam 11. The contact surface for a to be bent reinforcing steel mat 13, 13 (FIGS. 2 and 3) is disposed above the supporting beam 11 between the contact surface and the bending mandrels 12.

A bar engaging beam 15 is pivotally mounted via the arms 14 on the fixed supporting beam 11. The pivot supports for the arms 14 are designated with the reference numeral 16 in FIGS. 1 and 2. The bar engaging beam 15 can be swung about its pivot support by means of two hydraulic working cylinders 16a, which are operatively connected to a non-illustrated hydraulic power system.

A bending bar 18 is mounted on the bar engaging beam 15 by means of a pair of support arms 17, the longitudinal axis of the bending bar 18 being parallel to the longitudinal axis of the bending mandrel l2 and also to the longitudinal axis of the bar engaging beam 15. Hydraulic adjusting means are mounted in the connecting mechanism between the bending bar 18 and the supporting beam 11 and are generally referred to with the reference numeral 20 in FIG. 1. These hydraulic adjusting means are mounted at one end of the bending machine as can be seen from FIG. 1. The construction of these hydraulic adjusting means will be described hereinbelow.

In FIG. 1 a pair of hydraulic actuating cylinders 16a are illustrated which are pivotally connected at 19 to the swing arms 14. The piston rods of the hydraulic actuating cylinder 160 are pivotally connected at 21 through the support columns of the bending machine. The actuating cylinder 16a and their piston rods are, for sake of clarity, not illustrated in FIGS. 2 to 5.

As can be noted from FIGS. 2 to 4, the bar engaging beam consists, in a manner similar to the bar engaging beam of my co-pending application Ser. No. 288,152, filed Sept. 11, 1972 now US. Pat. No. 3,774,434, of two concentric pipes which are rotatable relative to each other, that is out of an exterior pipe 151 and an interior pipe 152. The support arms 17 of the bending bar 18 are secured to the outer pipe 151. The inner pipe 152 is connected by means of a pair of support arms 22 which extends through a pair of nonillustrated slits in the outer pipe 151 to the swing arms 14 which in turn are pivotally supported at 16 on the fixed supporting beam 11. The actuating cylinder 16, which is only illustrated in FIG. 1, are also connected to the swing arms 14 in a similar manner.

The relative position of those pipes 151 and 152 which form the bar engaging beam 15 is effected by means of the hydraulic adjusting means 20, which include a cylinder 201 which is pivotally mounted on the supporting beam 11 via an arm 23 about a pivot pin 24 which is parallel to the pivot pin 16. A double acting piston 202 is reciprocally mounted within the cylinder 201 and divides this cylinder into two cylindrical chambers 203 and 204. The piston rod 205 which extends outside of the cylinder 201 is pivotally connected by means of a pin 26 with the arm 25 which is secured to the outer pipe 151.

The hydraulic adjusting means of the embodiment illustrated in FIG. 2 includes a closed hydraulic system which is only schematically illustrated. This system has two conduits 205 and 206 which are in communication with the two chambers 203 and 204, said chambers being filled with hydraulic fluids. In the first conduit 205 there is mounted a valve 207 which can be selectively opened, while in the second conduit 206 there is mounted an excess pressure valve 208 which serves as a safety element. The two valves 207 and 208 could also be combined into a single valve which could be mounted in a single conduit disposed'between both cylindrical chambers 203 and 204. The piston 202 of the hydraulic adjusting means 20 can be adjusted relative to the cylinder 201 by opening the blocking valve 207 and thus there is also effected a turning of the outer pipe 151 relative to the inner pipe 152. The rotation of the outer pipe 151 also effects a rotation of the bending bar 18 which is firmly secured thereto and thereby changes the arcuate path ofv said bending bar 18 relative to the bending mandrel 12.

The hydraulic adjusting means 20 can also be constructed and arranged in such a way (non-illustrated) that the position of the closing valve 207 is made dependent from the angular position of the bar engaging beam 15. The adjustment ofthe blocking valve 207 can be effected mechanically, hydraulically, or electrically. By adjusting the blocking valve there can, for example, be effected an adjustment of the piston 202 during the swinging movement of the bar engaging beam 15, that is while the bending machine carries out a bending operation, to obtain a predetermined arcuate movement of the bending bar 18. The bending bar operation of the bending machine can be very exactly adjusted in the aforedescribed manner. By adjusting the blocking valve 207 in dependency of the movement of the bar engaging beam 15 and also of the excess pressure valve 208, the pressure force of the bending bar 18 can also be adjusted during the bending operation and thereby the machine can be adjusted to the bending reaction forces that occur during the bending operation. Thus, for example, a damage to the bending mechanism can be avoided by means of the excess pressure valve 208 when, for example, an incorrect adjustment of the path of movement of the bending bar 18 occurs which could cause the bending bar to contact one of the bending rolls 26 mounted on the bending mandrel (FIG. 2). When the reaction forces become excessively large the excess pressure valve 208 opens and an adjustment of the piston 202 relative to the cylinder 201 and consequently an adjustment of the bending bar 18 is effected.

The bending installation is illustrated in FIGS. 2 and 3 in solid lines in an inoperative position and in double lines in its operative position. In FIG. 2 the bending rolls 26 have been mounted on the bending mandrels 12 to effect a relatively large bending radius in the reinforcing steel mat, and the bending rod 18 has been adjusted by means of the hydraulic adjustment means 20 to carry out a bending operation with this relatively large bending radius. In FIG. 3, on the other hand, the steel bars of the reinforcing steel mat 30' are directly bent about the bending mandrels l2, and the bending bar 18 is correspondingly adjusted by means of the hydraulic adjusting means 20 to effect a smaller bending radius.

In FIGS. 4 and 5 there is illustrated a modified embodiment of the bending machine, in which the outer pipe 151' as well as the inner pipe 152' of the bar engaging beam are respectively provided with an arm 25' and 25". The hydraulic adjusting means 20' are mounted between both arms 25' and 25". The cylinder 201' is pivotally connected to the arm 25" and the piston rod 205' is pivotally connected to the arm 25'.

In a bending machine in which the bar engaging beam is not formed by two concentric pipes 151 and 152 but is formed out of a unitary beam, it would be necessary to suitably mount the hydraulic adjusting means 20 on the bar engaging beam and to adjustably mount the bending bar 18 thereon, the hydraulic adjusting means 20 being mounted between the bending bar and the bar engaging beam.

The bending machine in accordance with the invention when provided with an hydraulic adjusting means 20 which can adjust the bending bar 18 in a stepless manner relative to the bending mandrel makes it possible to precisely adjust during the bending operation the bending mechanism according to the strength of the to be bent reinforcing steel mat and according to the size of the bending radius thereby providing for an optimum use of the bending machine. Simultaneously the hydraulic adjusting means introduces a safety feature for the bending mechanism which avoids overloading, such as may occur when bending too strong reinforcing steel mats or due to a faulty adjustment of the bending machine.

Although the invention is illustrated and described with reference to a plurality of preferred embodiments thereof, it is to be expressly understood that it is in no way limited to the disclosure of such a plurality of preferred embodiments, but is capable of numerous modifications within the scope of the appended claims.

What is claimed is:

1. An arrangement for bending reinforcing steel mats, comprising in combination,

a fixed support bean having a bearing surface for supporting a reinforcing steel mat being formed by a plurality of rods;

a plurality of coaxial hook-like bending mandrels removably mounted on said fixed support beam over said bearing surface so that the rods of said steel mat can be inserted therebetween;

a bar engaging beam pivotally mounted in said arrangement relative to said fixed support beam about an axis which is parallel to the axes of said coaxial hook-like bending mandre'ls',

actuating means operatively connected to said bar engaging beam for pivoting it relative to said fixed support beam;

a bending bar adjustably mounted on said bar engaging beam so that its arcuate path relative to said fixed support beam can be selectively adjusted;

hydraulic adjusting means operatively connected, on the one hand, to said bending bar and, on the other hand, to said bar engaging beam;

said hydraulic adjusting means comprising a cylinder, a double acting piston reciprocally mounted in said cylinder and dividing it into two chambers, conduit means communicating said two chambers, and closeable valve means mounted in said conduit means;

said hydraulic adjusting means being adapted to steplessly adjust the position of said bar engaging beam relative to said bending bar and is connected to an hydraulic power source.

2. The arrangement as set forth in claim 1, wherein said conduit means comprises a first conduit disposed between said two chambers for conducting hydraulic fluid to adjust said piston relative to said cylinder, said first conduit being normally open but being adapted to be closed, a second conduit disposed between said two chambers, and an excess pressure valve mounted in said second conduit.

3. The arrangement as set forth in claim 2, wherein said closeable valve means and said excess pressure valve means are adjusted in dependency with the movement of said bending bar.

4. The arrangement as set forth in claim 3, wherein said bar engaging beam comprises two concentric pipes which are rotatable relative to each other, one of said pipes having at least one first arm which is connected to said bending bar and the other pipe having at least one second arm which is pivotally connected to said fixed support beam, said double acting piston having a piston rod extending from said cylinder, said piston rod being pivotally connected to said first arm and said cylinder being pivotally connected to said fixed support beam.

5. The arrangement as set forth in claim 4, wherein said cylinder pivots relative to said fixed support beam relative to an axis which is parallel to the axis of said other pipe.

6. The arrangement as set forth in claim 3, wherein said bar engaging beam comprises two concentric pipes which are rotatable relative to each other, one of said pipes having at least one first arm which is connected to said bending bar and the other pipe having at least one second arm which is pivotally connected to said cylinder, said double acting piston having a piston rod extending from said cylinder, including a third arm which is connected to one of said one pipe at one of its ends and is pivotally connected to said piston rod at its otherend. 

1. An arrangement for bending reinforcing steel mats, comprising in combination, a fixed support bean having a bearing surface for supporting a reinforcing steel mat being formed by a plurality of rods; a plurality of coaxial hook-like bending mandrels removably mounted on said fixed support beam over said bearing surface so that the rods of said steel mat can be inserted therebetween; a bar engaging beam pivotally mounted in said arrangement relative to said fixed support beam about an axis which is parallel to the axes of said coaxial hook-like bending mandrels; actuating means operatively connected to said bar engaging beam for pivoting it relative to said fixed support beam; a bending bar adjustably mounted on said bar engaging beam so that its arcuate path relative to said fixed support beam can be selectively adjusted; hydraulic adjusting means operatively connected, on the one hand, to said bending bar and, on the other hand, to said bar engaging beam; said hydraulic adjusting means comprising a cylinder, a double acting piston reciprocally mounted in said cylinder and dividing it into two chambers, conduit means communicating said two chambers, and closeable valve means mounted in said conduit means; said hydraulic adjusting means being adapted to steplessly adjust the position of said bar engaging beam relative to said bending bar and is connected to an hydraulic power source.
 2. The arrangement as set forth in claim 1, wherein said conduit means comprises a first conduit disposed between said two chambers for conducting hydraulic fluid to adjust said piston relative to said cylinder, said first conduit being normally open but being adapted to be closed, a second conduit disposed between said two chambers, and an excess pressure valve mounted in said second conduit.
 3. The arrangement as set forth in claim 2, wherein said closeable valve means and said excess pressure valve means are adjusted in dependency with the movement of said bending bar.
 4. The arrangement as set forth in claim 3, wherein said bar engaging beam comprises two concentric pipes which are rotatable relative to each other, one of said pipes having at least one first arm which is connected to said bending bar and the other pipe having at least one second arm which is pivotally connected to said fixed support beam, said double acting piston having a piston rod extending from said cylinder, said piston rod being pivotally connected to said first arm and said cylinder being pivotally connected to said fixed support beam.
 5. The arrangement as set forth in claim 4, wherein said cylinder pivots relative to said fixed support beam relative to an axis which is parallel to the axis of said other pipe.
 6. The arrangement as set forth in claim 3, wherein said bar engaging beam comprises two concentric pipes which are rotatable relative to each other, one of said pipes having at least one first arm which is connected to said bending bar and the other pipe having at least one second arm which is pivotally connected to said cylinder, said double acting piston having a piston rod extending from said cylinder, including a third arm which is connected to one of said one pipe at one of its ends and is pivotally connected to said piston rod at its other end. 